Semiconductor photonic devices, such as lasers, have an active structure in which electrons and holes are converted into photons to produce optical emissions. FIG. 1 illustrates a cross-sectional view of prior art semiconductor laser 100. When a positive electrode is connected to p-type electrical contact 106 and negative electrodes are connected to n-type electrical contacts 112, and a voltage is applied, laser 100 becomes forward biased. Electrical current (i.e., holes and electrons) is injected towards active layer 109. Holes in p-type region 108 move in a direction away from p-type electrical contact 106 toward n-type electrical contacts 112. Electrons in n-type layer 110 move in a direction away from n-type contacts 112 toward p-type electrical contact 106. The active structure of laser 100 includes optical mode 113 and the portion of active layer 109 included in optical mode 113. As the holes and electrons meet at the active structure, the holes and electrons combine to emit light.
Regions 107 are implanted in order to inhibit electrical conduction and force the electrical current to flow from p-type electrical contact 106 through region 111 and into the portion of active layer 109 that overlaps optical mode 113. Implant regions 107 present reliability issues for device 100, as proton implanted regions cannot be too close to the active region of the device due to concerns about implant damage causing current to spread and leak outside of the confined area
The prior art laser of FIG. 1 further includes silicon waveguide 104 formed on a silicon on insulator substrate that includes silicon top layer 101, silicon dioxide layer 102 and silicon substrate 103. Silicon waveguide 104 is formed by etched regions 105 included in silicon top layer 101.
Etched regions 105 cause several detrimental effects for laser 100. Creating said regions results in voids in the structure that reduce the mechanical strength of the device. These waveguide confinement structures further result in the device having poor thermal performance due to material loss where the material was etched away to form regions 105. The areas that heat may dissipate away from the laser's active region are also restricted due to regions 105 and layer 102. Prior art solutions to improve thermal performance have included creating thermal shunts in a lasing device, but this solution requires additional processing steps.
Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the inventive concepts presented herein. An overview of embodiments of the invention is provided below, followed by a more detailed description with reference to the drawings.